西安冬季可吸入颗粒物中多环芳烃的组成及风险评价

摘要

对2006-12-19～至2007-01-15采集的西安冬季昼夜大气可吸入颗粒物(PM_(10))样品,利用气相色谱-质谱联用仪(GS-MS)分析检测出美国EPA优先控制的12种多环芳烃(PAHs),结果显示,西安冬季大气PM_(10)中白天与夜晚总的PAHS平均质量浓度分别为312.0 ng·m~(-3)和346.0 ng·m~(-3),且PM_(10)中主要以4～5环的多环芳烃为主.采用苯并(a)芘(BaP)等效质量浓度(BaPE)评价PAHS的污染状况,结果表明,苯并(a)芘(BaP)白天及晚上的平均质量浓度分别为30.0 ng·m~(-3)和34.8 ng/m~3,计算得出西安冬季白天与晚上的BaPE平均值分别为45.3 ng·m~(-3)、51.0 ng·m~(-3),含量超过国家标准4.5倍以上.%PM_(10) samples were collected in Xi'an from 19 Dec 2006 to 15 Jan 2007 and the polycy-clic aromatic hydrocarbons (PAHs) concentration was measured using a gas chromatography -mass spectrometric (GC-MS). The total PAHs concentration ranged 174. 6-455.0 ng·m~(-3) in the daytime and 193. 9-515.4 ng·m~(-3) in the night. PAHs profiles were predominated by high rings components with 4-5 rings. The carcinogenic power of atmospheric PM_(10) PAHs was evaluated u-sing benzo (a) pyrene (BaP) and benzo(a)pyrene-equivalent carcinogenic concentration(BaPE). The results show that the average concentration of BaP was 30. 0 ng·m~(-3) in the daytime and 34. 8 ng·m~(-3) in the night. The average concentration of BaPE was 45. 3 ng·m~(-3) in the daytime and 51. 0 ng·m~(-3) in the night. The concentration of BaP observed in Xi'an was 4. 5 times greater than that in Chinese standard of environment air quality. PAHs sources were identified using source profiles of previous studies and it is likely that diesel vehicle exhaust and coal combustion are the main sources of PM_(10) PAHs in Xi'an during winter.